HARQ-ACK handling with multiple PUCCH in multi-TRP transmission in NR

ABSTRACT

The present disclosure relates to a user equipment, a network node and respective communication methods for a user equipment and a network node. A according to some embodiments, a user equipment comprises a transceiver which, in operation, receives data on a plurality of downlink shared channels, the data received on the plurality of downlink shared channels being respectively the same data, and circuitry which, in operation, decodes the data, generates an indicator which indicates whether or not the data has been successfully decoded using the plurality of downlink shared channels. The transceiver, in operation, transmits the indicator on at least one of a plurality of uplink control channels associated respectively with the plurality of downlink shared channels.

BACKGROUND Technical Field

The present disclosure relates to transmission and reception of signalsin a communication system. In particular, the present disclosure relatesto methods and apparatuses for such transmission and reception.

Description of the Related Art

The 3rd Generation Partnership Project (3GPP) works at technicalspecifications for the next generation cellular technology, which isalso called fifth generation (5G) including “New Radio” (NR) radioaccess technology (RAT), which operates in frequency ranges up to 100GHz. The NR is a follower of the technology represented by Long TermEvolution (LTE) and LTE Advanced (LTE-A). The NR is planned tofacilitate providing a single technical framework addressing severalusage scenarios, requirements and deployment scenarios definedincluding, for instance, enhanced mobile broadband (eMBB),ultra-reliable low-latency communications (URLLC), massive machine typecommunication (mMTC), and the like. For example, eMBB deploymentscenarios may include indoor hotspot, dense urban, rural, urban macroand high speed; URLLC deployment scenarios may include industrialcontrol systems, mobile health care (remote monitoring, diagnosis andtreatment), real time control of vehicles, wide area monitoring andcontrol systems for smart grids; mMTC may include scenarios with largenumber of devices with non-time critical data transfers such as smartwearables and sensor networks. The services eMBB and URLLC are similarin that they both demand a very broad bandwidth, however are differentin that the URLLC service requires ultra-low latencies. In NR, thePhysical layer is based on time-frequency resources (such as OrthogonalFrequency Division Multiplexing, OFDM in LTE) and may support multipleantenna operation.

For systems like LTE and NR, further improvements and options mayfacilitating efficient operation of the communication system as well asparticular devices pertaining to the system.

BRIEF SUMMARY

One non-limiting and exemplary embodiment facilitates providing robustand prompt signaling in communication using multiple transmission andreception points.

In one general aspect, the techniques disclosed herein feature a userequipment comprising a transceiver which, in operation, receives data ona plurality of downlink shared channels, the data received on theplurality of downlink shared channels being respectively the same data,and circuitry which, in operation, decodes the data, generates anindicator which indicates whether or not the data has been successfullydecoded using the plurality of downlink shared channels, wherein thetransceiver, in operation, transmits the indicator on at least one of aplurality of uplink control channels associated respectively with theplurality of downlink shared channels.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the following, exemplary embodiments are described in more detailwith reference to the attached figures and drawings.

FIG. 1 shows an exemplary architecture for a 3GPP NR system includingexemplary user and control plane architecture for the LTE eNB, gNB, andUE;

FIG. 2 is a schematic drawing showing an example PDSCH (physicaldownlink shared channel) data reception by a user equipment from pluraltransmission and reception points;

FIG. 3 is a schematic drawing showing an example of PUCCH (physicaluplink control channel) ACK (acknowledgement) transmission by a userequipment in a plural-TRP arrangement;

FIG. 4 is a schematic drawing showing another example of PUCCH (physicaluplink control channel) ACK (acknowledgement) transmission by a userequipment in a plural-TRP arrangement;

FIG. 5 is a schematic drawing showing a further example of PUCCH(physical uplink control channel) ACK (acknowledgement) transmission bya user equipment in a plural-TRP arrangement;

FIG. 6 is a block diagram showing an exemplary structure of a userequipment and a network node;

FIG. 7 is a block diagram showing an exemplary structure of a circuitryof a user equipment;

FIG. 8 is a flow chart showing an exemplary gNB communication method;

FIG. 9 is a graph schematically illustrating transmission, reception andprocessing of PDSCHs and PUCCHs according to an exemplary embodiment;

FIG. 10 is a flow chart showing an exemplary embodiment of a gNBcommunication method;

FIG. 11 is a graph schematically illustrating transmission, receptionand processing of PDSCHs and PUCCHs according to an exemplaryembodiment;

FIG. 12 is a flow chart showing an exemplary embodiment of a gNBcommunication method;

FIG. 13 is a graph schematically illustrating transmission, receptionand processing of PDSCHs and PUCCHs according to an exemplaryembodiment;

FIG. 14 is a flow chart showing an exemplary embodiment of a gNBcommunication method;

FIG. 15 is a graph schematically illustrating transmission, receptionand processing of PDSCHs and PUCCHs according to an exemplaryembodiment;

FIG. 16 is a flow chart showing an exemplary embodiment of a gNBcommunication method;

FIG. 17 is a graph schematically illustrating transmission, receptionand processing of PDSCHs and PUCCHs according to an exemplaryembodiment;

FIG. 18 is a flow chart showing an exemplary embodiment of a gNBcommunication method.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary example of a communication system including abase station and a terminal and a core network. Such communicationsystem may be a 3GPP system such as NR and/or LTE and/or UMTS. Forexample, as illustrated in FIG. 1 , the base station (BS) may be a gNB(gNodeB, e.g., an NR gNB) or an eNB (eNodeB, e.g., an LTE gNB). However,the present disclosure is not limited to these 3GPP systems or to anyother systems. Even though the embodiments and exemplary implementationsare described using some terminology of 3GPP systems, the presentdisclosure is also applicable to any other communication systems, and inparticular in any cellular, wireless and/or mobile systems.

A terminal is referred to in the LTE and NR as a user equipment (UE).This may be a mobile device such as a wireless phone, smartphone, tabletcomputer, or an USB (universal serial bus) stick with the functionalityof a user equipment. However, the term mobile device is not limitedthereto, in general, a relay may also have functionality of such mobiledevice, and a mobile device may also work as a relay.

A base station is a network node, e.g., forming a part of the networkfor providing services to terminals. A base station is a network node,which provides wireless access to terminals.

The physical layer in NR may provide multi-antenna operation such asMIMO (multiple input, multiple output) which may, for instance, includethe use of plural or multiple transmission and reception points(multi-TRP). For instance, a user equipment may receive data from pluralTRPs (transmission and reception points), wherein the plural-TRPs may becontrolled by the same or different network nodes. The terms multi-pointtransmission or coordinated multi-point transmission (CoMP) may also beused for multi-TRP communication or transmission.

The technologies described in the present disclosure are not limited toa particular arrangement of TRPs, or a particular relationship betweenTRPs and gNBs. Accordingly, for instance, multi-TRP operation may beperformed by a gNB having different antenna panels or radio headscorresponding to the TRPs and different radio frequency units operatingwith the respective antennas.

Moreover, in multi-TRP, several options are conceivable with respect tothe positional relationship between TRPs, and the distance between twoTRPs may vary. For instance, the TRPs may be close, so that a UEreceives signals from these TRPs from a similar angle. However, TRPs mayalso be located at a rather far distance from each other, for instanceat remote locations of a network cell. A UE being served by the two TRPsmay receive and transmit the signaling from and to the respective TRPson uncorrelated channels. Accordingly, gains in channel diversity may beoptimally utilized.

For instance, multi-TRP may be categorized into two high-levelcategories. Namely, the distinction between the categories may be madewith respect to the backhaul type of the backhaul link between two givenTRPs. On the one hand, an ideal backhaul is a very high throughput andvery low latency backhaul such as dedicated point-to-point connectionusing e.g., optical fiber. An ideal backhaul is assumed to allow forcommunication between the TRPs with approximately or almost 0 ms delay(e.g., for LTE-A, technical report 3GPP TR 36.932 V15.0.0 (2018-06)mentions in section 6.1.3 a one-way latency of less the 2.5 us wherein,however, propagation delay in the fiber/cable is not included). On theother hand, a non-ideal backhaul is a backhaul such as DSL, microwave,and other backhauls like relaying, and may for example involve finite(one-way) delays in the range of 2 ms or 5 ms for communication betweenthe two given TRPs.

Apart from the categorization into ideal backhauls and non-idealbackhauls, a further categorization in multi-TRP MIMO technology may bemade with respect to how baseband units are shared between TRPs. Forinstance, while there are different RF (radio frequency) blocks/unitsfor each of two given TRPs, the TRPs may share the same the samebaseband unit. Therein, the link between the RF units and the basebandunit may be ideal or non-ideal. Alternatively, there may be bothdifferent baseband and different RF blocks for each TRP. Therein, therespective links between baseband units and RF units as well as the linkbetween the different baseband units may be ideal or non-ideal.

The present disclosure provides approaches which may facilitatemulti-TRP operation and may particularly facilitate achievingreliability and robustness. The technologies disclosed may for instancefacilitate satisfying the requirements of URLLC by utilizing multi-TRPcommunication, but are not limited to URLLC use cases. For instance, thetechnologies disclosed may also be applied to eMBB and mMTC use cases.The present disclosure is applicable to scenarios including one or bothof ideal and non-ideal backhauls.

As mentioned above, multiple and far apart TRPs may allow for providingspatial diversity gains. The exploitation of these spatial diversitygains may in particular facilitate transmission and reception in a rangeof high frequencies where blockage for any of the links or wirelesscommunication channels between a TRP and a UE is particularly possible.In view of this, the techniques disclosed herein may facilitatecoordination between multiple points such as TRPs to schedule controlchannels and/or data channels.

An exemplary use case of multi-TRP coordination is illustrated in FIG. 2. Plural TRPs transmit the same data on respective physical downlinkshared channels (PDSCHs) to a UE. In FIG. 2 , two TRPs, TRP1 and TRP2,are shown which respectively transmit the same data on respectivephysical downlink shared channels, PDSCH1 and PDSCH2. However, thepresent disclosure is not limited to scenarios where two TRPs transmitthe same data to a UE. A plurality of TRPs transmitting the same datamay comprise two as well as a larger number of TRPs transmittingrespective PDSCHs. Accordingly, the present disclosure may be applied inuse cases were each TRP transmits its respective own PDSCH, and the samedata stream is used for the respective PDSCHs.

Moreover, two given PDSCHs among the plurality of PDSCHs respectivelybelonging to the plurality of TRPs may have the same or a respectivelydifferent MCS (modulation and coding scheme). Further, two given PDSCHsamong the plurality of PDSCHs may have the same or a differentredundancy version.

When in multi-TRP communication each TRP has a separate respectivePDSCH, but the separate PDSCHs all use the same data stream and conveythe same data, an issue arises of how to handle the HARQ-ACK (HybridAutomatic Repeat Request-Acknowledgement) feedback.

Some exemplary schemes of HARQ-ACK handling are shown in FIGS. 3 to 5 .Therein PUCCH1 is the uplink control channel on which the UE transmitscontrol data such as a HARQ-ACK feedback to TRP1, and PUCCH2 is thecontrol channel for uplink control transmissions from the UE to TRP2.HARQ-ACK1 is the HARQ-ACK feedback to PDSCH1 shown in FIG. 2 , andHARQ-ACK2 is the HARQ-ACK feedback to PDSCH2.

However, as will be described in the following, transmission/receptionschemes for physical control channels (PDCCH/PUCCH), such as exemplifiedby FIGS. 3 to 5 , might not optimally utilize and exploit the benefitsof multi-TRP transmission.

In FIGS. 3 and 4 , a single PUCCH (PUCCH1 in FIG. 3 and PUCCH2 in FIG. 2) carries both feedback signals HARQ-ACK1 and HARQ-ACK2. Such asingle-PUCCH transmission may face robustness issues since the used link(the link from UE to TRP1 in FIG. 3 , and the link from the UE to TRP2in FIG. 4 ) may be in blockage. Furthermore, the non-served TRP (TRP2 inFIG. 3 and TRP1 in FIG. 4 ) needs to be informed about the HARQ-ACK toits respective PDSCH, which may lead to an increased latency, inparticular if there is a non-ideal backhaul between TRP1 and TRP2.

The UE may also transmit respective PUCCHs with respective HARQ-ACKsignals to the plural TRPs. For instance, in FIG. 5 , the UE sendsPUCCH1 to TRP1, and respectively sends PUCCH2 to TRP2. However, in thecase of a NACK (negative acknowledgement) which the UE transmits in aPUCCH in response to a respective PDSCH from which it could notsuccessfully receive and/or decode the data, an unnecessaryretransmission from one of the TRPs which receives the NACK may occur ifthe other TRP (or at least one of the other TRPs in a case of more thantwo TRPs) received a (positive ACK) indicating that the data on itsrespective PDSCH could be successfully received and decoded. Since thedata stream is the same for both (or all) PDSCH, and the same data isconveyed on the PDSCHs, the correct reception and decoding of one of theplural PDSCHs from one of the respective plural TRPs is sufficient. Inparticular, a TRP which received the NACK might not receive backhaulcontrol signaling or receive it with some delay in case of non-idealbackhaul from another TRP that received an ACK. Delayed reception or noreception of the ACK from the other TRP may result in an unnecessaryretransmission.

The present disclosure provides a user equipment (UE) 610 comprising atransceiver 620 (transceiver/receiver) and circuitry 630. An exemplaryUE in accordance with the present disclosure is illustrated in FIG. 6 .

As can be seen from FIG. 6 , the present disclosure also provides anetwork node 660 to be further described below. UE and network node areconnected to and in communication with each other via a channel, forinstance a wireless channel, in a communication system. Moreover, the UEmay be in connection with one or more network nodes over respectivewireless channels, wherein, in the case of more than one network node,the network nodes are further in connection with each other via a(non-ideal or ideal) backhaul link.

In order to distinguish transceiver 620 and circuitry 630 comprised bythe UE 610 from a transceiver 670 and circuitry 680 comprised by thenetwork node, the terms “UE transceiver,” “UE circuitry,” “network nodetransceiver” and “network node circuitry” are also respectively used inthe description.

The UE transceiver 620, in operation, receives data on a plurality ofdownlink shared channels. The data (e.g., user data or higher-layer datafrom a layer higher than the physical layer) received respectively onthe plurality of downlink shared channels is the same data; forinstance, the data has been generated using the same data stream.

The UE circuitry 630 is processing circuitry which, in operation,decodes the data and generates an indicator which indicates whether ornot the data has been successfully decoded using the plurality ofdownlink shared channels. For instance, the UE circuitry 630 comprisesmulti-channel processing circuitry 635 (or plural-channel processingcircuitry). For instance, the multi-channel processing circuitry 635,which is exemplified by FIG. 7 , comprises multi-channel data decodingcircuitry 736 (e.g., multi-PDSCH data decoding circuitry) and decodingresult indicator generation circuitry 737 (e.g., common ACK/NACKgeneration circuitry).

The UE transceiver 620, in operation, transmits the indicator generatedby the UE circuitry 630 on at least one of a plurality of uplink controlchannels. Therein, the plurality of uplink control channels areassociated respectively with the plurality of downlink shared channels.

For instance, the plurality of downlink channels and the respectivelycorresponding plurality of uplink control channels are PDSCHs andPUCCHs, as used in LTE, LTE-A, or NR, used to transmit identical datausing a plurality of HARQ processes which may respectively include aninitial transmission and, if necessary, one or more retransmissions. APUCCH associated with a respective PDSCH carries a HARQ-ACK signal (ACKor NACK) indicating whether or not the data has been successfullydecoded. Although the PUCCH responds to a respective PDSCH (e.g., PUCCH1associated with PDSCH1, PUCCH2 associated with PDSCH2, etc.), theindicator included in the HARQ-ACK signal indicates successful decodingusing the plurality of PDSCHs rather indicating the result obtainedusing only the respective PDSCH.

The plurality of PDSCHs may be transmitted by one or more network nodesin the same transmission time interval (TTI), and may further bereceived using the same frequency, frequencies or bandwidth part.Moreover, the plurality of PUCCHs may be transmitted in the same TTI.Accordingly, when referring to a plurality of PDSCHs/PUCCHs, the presentdisclosure does not refer a plurality of (re)transmissions within asingle HARQ process, but describes a plurality of HARQ processes bywhich transmission of identical data is performed. As will be describedfurther below, a plurality of interrelated or linked HARQ processes forthe transmission of the same data may be considered to constitute amulti-TRP HARQ process.

However, the plurality of PDSCHs may differ in the spatial directionsfrom which they are transmitted to/received by the UE, and/or respectivebeams on which they are sent. Further, depending on the embodiment, asdescribed further below, the MCS and/or redundancy versions used forencoding and transmitting the data in two given HARQ processes among theplurality of HARQ processes may be the same or different.

Corresponding to the above-mentioned UE and the network node, thepresent application further provides a communication method for a UE anda communication method for a network node.

The communication method for a UE, as shown in FIG. 8 , comprises thestep of receiving S810 data on a plurality of downlink shared channels,wherein the data received on the plurality of downlink shared channelsis respectively the same data. The method further comprises the steps ofdecoding S820 the data and generating S830 an indicator which indicateswhether or not the data has been successfully decoded using theplurality of downlink shared channels. Moreover, the method comprises astep of transmitting S840 the indicator on at least one of a pluralityof uplink control channels associated respectively with the plurality ofdownlink shared channels.

When, in accordance with the above description of apparatuses (UE andnetwork node) and corresponding methods, the UE 610 receives separatePDSCHs from among a plurality of PDSCHs from each of a plurality of TRPs(e.g., PDSCH1 from TRP1 and PDSCH2 from TRP2), the UE sends back acommon (e.g., a combined) HARQ-ACK result (for instance a common orcombined HARQ-ACK result bit) to one, more, or each TRP from among theplurality of TRPs using respectively one or more separate PUCCHs, suchas PUCCH1 (to TRP1) and PUCCH2 (to TRP2).

Accordingly, techniques disclosed herein may facilitate providingrobustness as they provide for HARQ-ACK information to be received atleast by one TRP while one or more of the remaining TRPs is/are inblockage. Moreover, the present invention may facilitate reducingbackhaul latency in the exchange of the HARQ-ACK information between theplurality of TRPs, as the plural TRPs will receive the same (i.e.,common ACK/NACK) information.

In the following, several exemplary embodiments of the presentdisclosure will be described.

For instance, the UE transceiver 620, in operation, transmits theindicator on each of the plurality of uplink control channels associatedrespectively with the plurality of uplink control channels. A firstexample is shown in FIG. 9 .

In FIG. 9 (as well as FIGS. 11, 13, 15, and 17 ), the respectivedownlink shared channels and uplink control channels are shown ashatched portions embedded in rectangular shapes. The rectangular shapesrepresent temporal units such as TTIs in which the transmission of therespective physical channel is performed, e.g., slots or temporal unitsbelow the slot level, depending on whether slot-based or non-slot-basedcommunication is performed and on the particular numerology definingsubcarrier spacing of the physical, in particular time (symbol) andfrequency resources, resources. However, the depicted arrangement ofhatched portions within rectangles is merely schematic and not intendedto limit the present disclosure to any particular allocation of physicalchannels to particular physical resources within a TTI. Moreover, arectangle may also represent temporal resources including a plurality ofTTIs. Moreover, the respective channel names have been reproducedadjacent to the hatched portions to enhance readability.

In general, TTI determines the timing granularity for schedulingassignment. One TTI is the time interval in which given signals ismapped to the physical layer. For instance, conventionally, the TTIlength can vary from 14-symbols (slot-based scheduling) to 2-symbols(non-slot based scheduling). Downlink and uplink transmissions arespecified to be organized into frames (10 ms duration) consisting of 10subframes (1 ms duration). In slot-based transmission, a subframe, inreturn, is divided into slots, the number of slots being defined by thenumerology/subcarrier spacing and the specified values range between 10slots for a subcarrier spacing of 15 kHz to 320 slots for a subcarrierspacing of 240 kHz. The number of OFDM symbols per slot is 14 for normalcyclic prefix and 12 for extended cyclic prefix (see section 4.1(general frame structure), 4.2 (Numerologies), 4.3.1 (frames andsubframes) and 4.3.2 (slots) of the 3GPP TS 38.211 V15.0.0 (2017-12)).However, assignment of time resources for transmission may also benon-slot based. In particular, the TTIs in non slot-based assignment maycorrespond to mini-slots rather than slots. I.e., one or more mini-slotsmay be assign to a requested transmission of data/control signaling. Innon slot-based assignment, the minimum length of a TTI mayconventionally be 2 OFDM symbols.

In several exemplary embodiments, the UE transceiver 620, in operationreceives the plurality of downlink shared channels respectively from aplurality (two or more) of TRPs, such as TRP1 and TRP2 shown in FIG. 2 .In some of these embodiments, the UE transceiver 620 transmits theindicator on each of the plurality of uplink control channelsrespectively to the plurality of TRPs. Accordingly, a downlink sharedchannel and a corresponding uplink control channel are receivedfrom/transmitted to the same TRP. In these cases, an uplink channel anda downlink channel associated with the uplink channel are links betweena UE and the same TRP.

It should be noted that although the disclosure provides some examplesof a scenario with two TRPs, the above and following embodiments aredirectly and analogously applicable to multi-TRP scenarios using morethan two TRPs.

Furthermore, as mentioned above, the respective downlink shared channels(e.g., PDSCHs) transmit the same data using the same data stream.Accordingly, it is required that this same data is available to each ofthe plurality of TRPs, for instance made available between the TRPs by abackhaul link. In an exemplary, non-limiting scenario, the respectiveTRPs have the same baseband unit but respectively different RF blocksfor each of the plurality of TRPs. In this scenario, the link betweenthe plurality of RF units to the baseband unit may be non-ideal.However, since this exemplary scenario is non-limiting, the previous andthe following embodiments may also be applied to any other combinationsof single and multiple baseband units connected to each other and to therespective RF units by ideal or non-ideal backhaul links, if noindication to the contrary is made and/or the context does not indicatethe contrary.

In some embodiments, the indicator generated and transmitted by the UEis a common or combined indicator which indicates a common result ofdecoding using at least two downlink shared channels among the pluralityof downlink shared channels. In particular, the common indicator is aone-bit indicator. Moreover, the common result may be a result which isbased on each of the plurality of downlink shared channels.

Accordingly, a single HARQ-ACK bit (i.e., the common indicator orcombined indicator) indicates successful decoding based on a processingperformed by the UE circuitry 630 on a plurality of instances of thesame data included respectively in the plurality of downlink sharedchannels. For instance, the data from the plurality of downlink sharedchannels may be combined to generate a single combined code word beforethe decoding is performed. Alternatively, the plurality of instances ofthe data from the respective PDSCHs may first be processed separately,and then a single combined HARQ-ACK bit is generated based on theplurality of decoding results.

Combining of Decoding Results

In some embodiments, as shown in FIG. 9 , the UE circuitry 630, inoperation, respectively (individually) decodes the code wordscorresponding to and representing the same data respectively in theplurality of PDSCHs determines whether the decoding of each of therespective code words from the plurality of PDSCHs has been successful.For instance, the UE circuitry performs CRCs (cyclic redundancy check)respectively on the decoded data to determine whether decoding has beensuccessful. Based on the results of the respective checks, the UEcircuitry 630 generates respective indicators (e.g., one-bit indicators)indicating the respective results of the CRCs. Based on the respectiveindicators or on the individual results of decoding and CRC usingchecking the respective PDSCHs, the UE circuitry generates the commonindicator.

For instance, the processing circuitry respectively decodes theplurality of downlink shared channels, performs a logical (or binary)“OR” operation on the respective results of the decoding of theplurality of downlink shared channels. The common indicator is a one-bitindicator indicating the respective results of the logical “OR”operation. Each PDSCH from among the plurality of PDSCHs (transmittedrespectively from the plurality of TRPs) is individually decoded by theUE circuitry 630, and the individual HARQ-ACK results or bits from therespectively performed CRCs are combined by applying a logical “OR”function on the respective bits to generate the common indicator assingle bit. The single bit (i.e., the value indicating the result of thelogical “OR” operation) may be transmitted on each of the plurality ofPUCCHs to the respective TRPs from among the plurality of TRPs.

The present disclosure is not limited to any particular implementationof a logical “OR” function/operation. It is sufficient that an operationis performed which determines whether or not the data has beensuccessfully received and decoded by individual processing (decoding andCRC) of the data from at least one of the plurality of PDSCHs. Acombined HARQ-ACK bit having a (positive) ACK value is generated atleast one of the individual decoding processes has been successful, anda combined HARQ-ACK bit having a value representing a NACK is generatednone of the individual decoding processes using the respective PDSCHswas successful.

For instance, in the case of two PDSCHs shown in FIG. 9 , a combinedHARQ-ACK result bit is generated by performing a logical “OR” functionbetween individual respective HARQ-ACK bits, HARQ-ACK1 and HARQ-ACK 2with respect to the corresponding downlink shared channels, PDSCH1 andPDSCH2, respectively.

FIG. 10 shows an exemplary embodiment of a communication method for a UEaccording to some embodiments wherein a logical “OR” function isperformed. In the receiving step S1010, the UE receives the same data inPDSCH1 and PDSCH 2. Step S1020 includes individual decoding using therespective PDSCHs, respectively performing CRCs and generatingrespective HARQ-ACK indicators HARQ-ACK1 and HARQ-ACK2 correspondingrespectively to the plurality of PDSCHs. An “OR” function is performedin step S1030 to generate a combined HARQ-ACK bit (which may e.g., benamed “HARQ-ACK_comb”) representing the common result of decoding thedata using the plurality of PDSCHs. The method shown in FIG. 10 furthercomprises, as a transmission step S1040, transmitting the result of theapplication of the “OR” function as the combined HARQ-ACK bit on each ofthe respective PUCCHs associated with the respective PDSCHs.

The embodiments of the present disclosure in which a logical “OR”operation is applied on individual decoding results of PDSCHs mayfacilitate providing transmission efficiency because even if one PDSCHamong the plurality of PDSCHs is correctly decoded, no retransmissionfrom any of the plurality of TRPs needs to be performed. In addition,these embodiments may be utilized when different MCS (or differentredundancy versions) are utilized respectively on different PDSCHs.

The present disclosure may facilitate exploiting spatial diversity byusing respective downlink shared channels from a plurality of TRPs andby transmitting the same common indicator on a plurality of uplinkcontrol channels to the respective PDSCHs. However, in some cases, itmay be sufficient if the combined indicator is sent on one PUCCH to oneof the plurality of TRPs. Still, as shown in FIGS. 9 and 10 describedabove, each of the plurality of PDSCHs from the respective TRPs isindividually decoded at the UE, and the HARQ-ACK results of each CRCperformed on a respective decoding result of the plurality of PDSCHs iscombined using the above-mentioned logical “OR” function. However, asshown in FIG. 11 , the single bit resulting from the logical “OR”operation S1030 is transmitted on PUCCH1 only.

For instance, as shown in FIG. 12 steps S1010 to S1030 are the same asin the method illustrated FIG. 10 . However, in the transmission stepS1240, the UE transmits the combined HARQ-ACK bit resulting from thelogical “OR” operation on PUCCH1 only.

In particular, if the uplink channel quality between UE and TRP2 is poorin comparison with the channel quality on the uplink between the UE andTRP1, it may be unnecessary to transmit the common indicator to TRP2.Moreover, an ideal backhaul link between the respective TRPs mayfacilitate compensating the omitted PUCCH transmission to TRP2. Also, inthe case of a wide beam and two TRPs located relatively close to eachother, a single PUCCH transmission may be sufficient for being receivedat both TRPs.

Furthermore, in some exemplary embodiments where the combined indicatoris sent on each of the plurality of uplink control channels, arespective indicators may be transmitted on each of the correspondinguplink control channel as well.

For instance, the UE circuitry 630, in operation, generates for each ofthe plurality of downlink shared channels, a respective indicatorindicating whether or not the data has been successfully decoded usingthe respective downlink shared channel. The UE transceiver 620, inoperation, transmits, on each of the plurality of uplink controlchannels, the common indicator (the combined HARQ-ACK bit describedabove) and the respective indicator indicating the result of decodingthe downlink shared channel associated respectively with the uplinkcontrol channel. Accordingly, in addition to the combined one-bitHARQ-ACK indicator, a respective single-channel or individual HARQ-ACKindicator (e.g., respective bits HARQ-ACK1 and HARQ-ACK2) is transmittedrespectively on each of the plurality of uplink control channels (e.g.,PUCCH1 and PUCCH2) to the respective TRPs.

The transmission of a plurality of individual HARQ-ACK bits onrespective PUCCHs may be useful from the point of view of channelquality indication as well as link adaptation and/or dynamic pointselection. For instance, when a NACK indicated by an individual HARQ-ACKindicator received by one of the TRPs, a TRP different from this TRPreceiving the NACK may be selected for performing subsequent PDSCHtransmissions as one of the plurality of TRPs to replace the TRP thathas received the NACK in later TTIs.

In some exemplary embodiments, the UE transceiver, in operation,transmits, on each of the plurality of uplink control channels, anACK/NACK signal including the common (combined) indicator generatedbased on the logical “OR” operation and the respective individualindicator indicating successful or unsuccessful decoding of the datatransmitted on the respective PDSCH from the respective TRP.Accordingly, a plurality of ACK/NACK signals transmitted respectively onthe plurality of PUCCHs each contain two HARQ-ACK bits, namely a commonindicator (one-bit indicator) and a respective indicator which may be aone-bit indicator as well.

The generation and transmission of individual respective indicators inaddition to the single combined HARQ-ACK bit is schematicallyillustrated in FIG. 13 by additional arrows between the respectivePDSCHs and PUCCHs which are added with respect to FIG. 9 . Acommunication method for a UE transmitting a plurality of respectiveindividual indicator in addition to the individual indicator is shown inFIG. 14 . In the method, transmission step 1440 differs from step 1040shown in FIG. 10 in that the UE transmits the combined indicator and theindividual indicator HARQ-ACK1 on PUCCH1 and by transmitting thecombined bit and the individual HARQ-ACK2 indicator on PUCCH2 ratherthan transmitting only the combined indicator on both PUCCHs.

However, for the case where a respective bit on each of the plurality ofPUCCHs is provided in addition to the common one-bit indicator, thepresent disclosure is not limited to the respective indicator and thecommon indicator being signaled within a single signal (HARQ-ACK signal)or simultaneously in the same transmission instance. In particular, therespective indicators may already be signaled before the generation ofthe common indicator has been accomplished.

Accordingly, in some embodiments, the UE transceiver 620, in operation,transmits the respective indicator on each of the plurality of uplinkcontrol channels before the UE circuitry performs or accomplishedperforming the logical “OR” operation or the generation of the commonindicator.

This is shown in FIG. 15 where an example of two downlink sharedchannels, PDSCH1 and PDSCH2 and respective corresponding uplink controlchannels, PUCCH1 and PUCCH2, are shown. As can be seen, there are twoinstances of each of the two uplink control channels. These twoinstances of the same uplink control channel symbolize that theindividual (respective) HARQ-ACK indicators are signaled at differenttime instances or transmission instances than the common HARQ-ACKindicators. For instance, on each of the plurality of PUCCHs, the commonindicator may be signaled in the TTI adjacently subsequent to the TTIwhere the individual HARQ-ACK indicator is transmitted. However,dependent on the latency requirements of a particular use case, theremay be one or more TTIs between the TTIs in which the individual andrespectively, the common indicator is transmitted. As another example,the respective and the common indicator are transmitted on the same TTI,wherein they may be transmitted on respectively different PUCCHs whichare both associated with the respective PDSCH. Moreover, the drawing ofFIG. 15 is merely schematic, and the present disclosure is not limitingwith respect to whether the individual and the common indicator in thesame PUCCH are transmitted using the same or differentfrequencies/bandwidths.

First, the individual respective indicators or HARQ-ACK indicatorscorresponding respectively to one of the plurality of PDSCHs arerespectively transmitted on plurality of PUCCHs.

Second, the combined HARQ-ACK bit, e.g., the result of the logical “OR”operation, is sent on each PUCCH.

An exemplary embodiment of a communication method for a UE forseparately transmitting the individual and the combined HARQ-ACKindicator is shown in FIG. 16 . In contrast to communication methods ofprevious embodiments, a transmission step S1625 is included where theHARQ-ACK1 and the HARQ-ACK2 (the respective indicators) are transmittedrespectively on PUCCH1 and PUCCH2 on a first time instance. In a furthertransmission step S1640, the common indicator (the combined HARQ-ACKbit) is transmitted on both PUCCH1 and PUCCH2 (or, more generally, eachof the plurality of PUCCHs) on second transmission instance.

As indicated with respect to the embodiments described above withrespect to FIGS. 14 and 15 , the individual HARQ-ACK bits may facilitatechannel quality indication/estimation, radio link adaptation and/ordynamic point (TRP) selection. However, in the currently describedembodiments, the combined HARQ-ACK bit is transmitted later than therespective individual HARQ-ACK bits as its generation might be delayedwith respect to the individual respective decoding and CRC processes.Moreover, a faster or timelier transmission of the individual HARQ-ACKbits may be facilitated.

In the embodiments described above, the common indicator is a one-bitindicator which is generated by performing an operation such as alogical “OR” on the respective decoding/CRC results of the PDSCH data.However, as an alternative to generating such a common indicator, thepresent application also provides embodiments in which the commonindicator includes a plurality of bits respectively representingdecoding success of the plurality of PDSCHs.

Accordingly, in some embodiments, the common indicator includes aplurality of bits each of which indicates whether or not the data hasbeen successfully decoded using a respective one of the plurality ofdownlink shared channels.

For instance, in a scenario with two TRPs respectively transmittingPDSCHs, a value “10” may indicate that the data has been successfullydecoded from PDSCH1 and not successfully decoded from PDSCH2.

The present embodiments with a common indicator including plural bitsmay facilitate reducing the processing performed by a UE since a logicaloperation such as a binary “OR” function need not be performed togenerate the common indicator. In particular, such embodiments mayfacilitate HARQ-ACK processes when the number of TRPs (PUCCHs) is nottoo large, for instance if there are two TRPs actively transmitting thedata. However, for large numbers of TRPs transmitting the same data tothe UE on respective PDSCHs, any of the aforementioned embodiments usingthe one-bit indicator may facilitate keeping the signaling overheadsmaller.

Combining of Received Data

According to some embodiments described above, the decoding (and CRC)has been separately performed using the plurality of PDSCHs, and acommon one-bit indicator has been based on processing, e.g., a logical“OR” operation, on the individual decoding results.

However, the data received on the respective PDSCHs may be combined(e.g., by applying soft-combining) rather than the decoding results, andthe decoding and CRC is performed on the combined data/code word. Thecombined HARQ-ACK bit/common indicator is generated by soft-combiningthe signals received respectively from each TRP, and by performing asingle CRC check.

According to some embodiments, the UE circuitry 630, in operation,performs soft-combining on the data received on the plurality ofdownlink shared channels, decodes the combined data obtained by thesoft-combining, and generates the indicator based on the result of thedecoding of the combined data.

When soft-combining is applied, the respective instances of the samedata from the plurality of PDSCHs, e.g., a plurality of code words ordata packets, may for instance be combined either on a bit-by bit basisor on a (OFDM) symbol-by-symbol basis. In order for soft-combining to beapplied, the respective data packets received on the plurality of PDSCHshave the same number of bits/symbols. Accordingly, embodiments usingsoft-combining are utilized when the same MCS is used for the pluralityof PDSCHs, e.g., PDSCH1 and PDSCH2.

The data received on a plurality of PDSCHs respectively from a pluralityof TRPs is soft-combined by the UE, a combined CRC is generated, and theresult of the combined CRC is transmitted to each of the plurality ofPDSCHs. Accordingly, as shown in FIG. 17 , a single combined HARQ-ACKbit (the common indicator which is a one-bit indicator as in someabove-described embodiments) is generated by performing a CRC ofsoft-combined data.

A communication method according to some embodiments is shown in FIG. 18, which includes a soft-combining step S1815 of soft-combining the datareceived on the plurality of PDSCHs, e.g., PDSCHs and PDSCH2. In thedecoding step S1825, the UE circuitry 630 decodes the combined data,performs a CRC on the decoded data, and generates the common indicatorwhich indicates whether or not the combined data has been successfullydecoded.

In addition to soft-combining the data from the plurality of PDSCHs, ifthe transmissions is a retransmissions a plurality of HARQ-ACKprocesses, the combined code-word may further be soft-combined with acode word obtained in one or more previous transmissions.

The embodiments which apply soft-combining provide a single bit ofHARQ-ACK information without previously generating respective HARQ-ACKbits. They may facilitate making the HARQ-ACK information available ateach of the plurality of TRPs transmitting the PDSCHs without need foran ideal backhaul.

As mentioned above and shown in FIG. 6 , in relation with any of theprevious embodiments, the present disclosure provides a network node660, e.g., a NR base station/gNB, comprising a transceiver 670 andcircuitry 680. The network node transceiver 670, in operation, transmitsdata on a downlink shared channel from among a plurality of downlinkshared channels. The data transmitted on the plurality of downlinkshared channels is respectively the same data (e.g., the same datastream is used). On an uplink control channel associated with thedownlink shared channel, the network node transceiver 670, in operation,receives an indicator which indicates whether or not the transmitteddata has successfully been received and decoded using the plurality ofdownlink shared channels. The network node circuitry 680, in operation,determines based on the indicator, whether or not the d data has beensuccessfully received and decoded. For instance, the network nodecircuitry 680 comprises multi-channel processing circuitry 685 which, inoperation, determines whether the data has been successfully decodedusing at least one of the plural or multiple downlink shared channels.

Corresponding to the network node 660, the present disclosure furtherprovides a communication method for a network node. The network nodecommunication method comprises a step of transmitting data on a downlinkshared channel from among a plurality of downlink shared channels. Thedata transmitted on the plurality of downlink shared channels isrespectively the same data. The method further comprises a receivingstep of receiving, on an uplink control channel associated with thedownlink shared channel, an indicator which indicates whether or not thetransmitted data has successfully been received and decoded using theplurality of downlink shared channels, and a step of determining, basedon the received indicator, whether or not the data has been successfullyreceived and decoded.

For instance, the network node transmits the data on the PDSCH to a UE,and the PDSCH is one of a plurality of PDSCHs received by the UE from aplurality of TRPs. On each of the plurality of PDSCHs and correspondingPUCCHs, a respective HARQ-ACK process may be performed.

Based on the determination using the indicator whether or not the datahas been successfully decoded by the UE receiving the PDSCHs, thenetwork node continues or terminates the HARQ process. The HARQ processis terminated and no further retransmission is made if the commonindicator indicates the value of a (positive) ACK. Accordingly, if thedata could be successfully decoded based on the result of soft combiningor based on transmission successful decoding of at least one PUSCH, nomore repetition is performed in the PDSCH and in any of the plurality ofPDSCHs transmitted respectively from the plurality of TRPs. Aretransmission at least one or in any PUSCH only needs to be made ifnone of the decoding process of the data using any PDSCH was successful.

The plurality of HARQ-ACK processes thus perform transmission of thesame data, for instance in multi-TRP communication. Each of theplurality of PUCCHs is received by respectively the same TRP from whichthe PDSCH with which the PUCCH is associated has been transmitted.

As indicated above, different associations between one or more basestations and the plurality of TRPs are possible.

In some exemplary embodiments, the PDSCH used in the transmission by thenetwork node may be a first downlink channel from among the plurality ofdownlink shared channels. The network node transceiver 670 comprises afirst TRP and, in operation, transmits the data on the first downlinkshared channel using the first TRP, receives the indicator on the uplinkcontrol channel associated with the first downlink shared channel usingthe first TRP. The network node further comprises a backhaul interfaceand transmits, over the backhaul interface, scheduling information forscheduling transmission of the data a second downlink shared channelfrom among the plurality of downlink shared channels by a second TRP.

For instance, the backhaul interface may be an interface to a backhaullink from a baseband unit of the gNB to a RF unit which controls RFoperation of the second TRP, wherein the second TRP and the RF unit maybe included or associated with the network node.

Alternatively, the backhaul interface may be an interface to a backhaullink from the network node (or its baseband unit) to a baseband unitwhich may be associated with and/or comprised by a different (remotenetwork) network node.

A backhaul link may be used for transmitting and receiving the dataand/or control information to or from two or more given network nodestransmitting the data using respective TRPs in respective HARQ-ACKprocesses, or for transmitting and/or receiving scheduling data forscheduling transmission/reception on the respective HARQ processes.

The respective HARQ-ACK processes performed using the plurality of TRPsmay be considered as a single multi TRP HARQ process which includestransmission using a plurality of PUSCHs and corresponding PUCCHs. Inparticular, the HARQ process is terminated, and no more retransmissionis made if the data has been successfully decoded irrespective of theparticular PDSCH or PDSCHs from which successful decoding could beperformed.

A complete multi-TRP HARQ-ACK process may use the same plurality of TRPsin each transmission. However, the TRPs, and thus the PDCCHs, may beswitched either between HARQ-ACK processes for a given UE or betweensubsequent transmissions of a multi-TRP HARQ-ACK process. Switchingamong sets of TRPs respectively comprising (at least partially)different TRPs may be scheduled using a PDCCH. Moreover, coordinationinformation, which also may include an indication which TRPs are to beused for a subsequent transmission, may be transmitted from a networknode to another network node and/or to one or more TRPs using thebackhaul.

In some embodiments, the data is transmitted on two given PDSCHs usingrespectively different modulation and coding schemes (MCS). Forinstance, the network node circuitry encodes the data for transmissionon a first downlink shared channel among the plurality of downlinkchannels using a first MCS different from a second MCS used fortransmitting the data on a second downlink shared channel from among theplurality of downlink shared channels. As mentioned above, the seconddownlink shared channel is transmitted from a TRP different from the TRPused for transmission of the first downlink shared channel. Respectivelydifferent MCS may be used if the UE performs and decodes and CRC checksthe data from the respective PDSCHs separately, as described above.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be partly or entirelyrealized by an LSI such as an integrated circuit, and each processdescribed in the each embodiment may be controlled partly or entirely bythe same LSI or a combination of LSIs. The LSI may be individuallyformed as chips, or one chip may be formed so as to include a part orall of the functional blocks. The LSI may include a data input andoutput coupled thereto. The LSI here may be referred to as an IC, asystem LSI, a super LSI, or an ultra LSI depending on a difference inthe degree of integration. However, the technique of implementing anintegrated circuit is not limited to the LSI and may be realized byusing a dedicated circuit, a general-purpose processor, or aspecial-purpose processor. In addition, a FPGA (Field Programmable GateArray) that can be programmed after the manufacture of the LSI or areconfigurable processor in which the connections and the settings ofcircuit cells disposed inside the LSI can be reconfigured may be used.The present disclosure can be realized as digital processing or analogueprocessing. If future integrated circuit technology replaces LSIs as aresult of the advancement of semiconductor technology or otherderivative technology, the functional blocks could be integrated usingthe future integrated circuit technology. Biotechnology can also beapplied.

The present disclosure can be realized by any kind of apparatus, deviceor system having a function of communication, which is referred as acommunication apparatus.

Some non-limiting examples of such communication apparatus include aphone (e.g., cellular (cell) phone, smart phone), a tablet, a personalcomputer (PC) (e.g., laptop, desktop, netbook), a camera (e.g., digitalstill/video camera), a digital player (digital audio/video player), awearable device (e.g., wearable camera, smart watch, tracking device), agame console, a digital book reader, a telehealth/telemedicine (remotehealth and medicine) device, and a vehicle providing communicationfunctionality (e.g., automotive, airplane, ship), and variouscombinations thereof.

The communication apparatus is not limited to be portable or movable,and may also include any kind of apparatus, device or system beingnon-portable or stationary, such as a smart home device (e.g., anappliance, lighting, smart meter, control panel), a vending machine, andany other “things” in a network of an “Internet of Things (IoT).”

The communication may include exchanging data through, for example, acellular system, a wireless LAN system, a satellite system, etc., andvarious combinations thereof.

The communication apparatus may comprise a device such as a controlleror a sensor which is coupled to a communication device performing afunction of communication described in the present disclosure. Forexample, the communication apparatus may comprise a controller or asensor that generates control signals or data signals which are used bya communication device performing a communication function of thecommunication apparatus.

The communication apparatus also may include an infrastructure facility,such as a base station, an access point, and any other apparatus, deviceor system that communicates with or controls apparatuses such as thosein the above non-limiting examples.

According to some embodiments, the present disclosure provides a userequipment comprising a transceiver which, in operation, receives data ona plurality of downlink shared channels, the data received on theplurality of downlink shared channels being respectively the same data,and circuitry which, in operation, decodes the data, generates anindicator which indicates whether or not the data has been successfullydecoded using the plurality of downlink shared channels, wherein thetransceiver, in operation, transmits the indicator on at least one of aplurality of uplink control channels associated respectively with theplurality of downlink shared channels.

In some embodiments, the transceiver, in operation, transmits theindicator on each of the plurality of uplink control channels associatedrespectively with the plurality of downlink shared channels.

For instance, the transceiver, in operation, receives the plurality ofdownlink shared channels respectively from a plurality of TRPs,transmission and reception points, and transmits the indicator on theplurality of uplink control channels respectively to the plurality ofTRPs.

According to some embodiments, the indicator is a common indicator whichindicates a common result of decoding using at least two downlink sharedchannels among the plurality of downlink shared channels, the commonindicator being a one-bit indicator.

For example, the circuitry, in operation, respectively decodes theplurality of downlink shared channels, performs a logical “OR” operationon respective results of the decoding of the plurality of downlinkshared channels, and the common indicator indicates the result of thelogical “OR” operation.

In some exemplary embodiments, the circuitry, in operation, generates,for each of the plurality of downlink shared channels, a respectiveindicator indicating whether or not the data has been successfullydecoded using the respective downlink shared channel, and thetransceiver, in operation, transmits, on each of the plurality of uplinkcontrol channels, the common indicator and the respective indicatorindicating the result of decoding the downlink shared channel associatedrespectively with the uplink control channel.

For instance, the transceiver, in operation, respectively transmits, oneach of the plurality of uplink control channels, an ACK/NACK,acknowledgement/negative acknowledgement signal including the commonindicator and the respective indicator.

In some embodiments, transceiver, in operation, transmits the respectiveindicator on each of the plurality of uplink control channels before thecircuitry accomplishes performing the logical “OR” operation.

In some embodiments, the circuitry, in operation, respectively decodesthe plurality of downlink shared channels, and the indicator includes aplurality of bits each of which indicates whether or not the data hasbeen successfully decoded using a respective one of the plurality ofdownlink shared channels.

For example, the data received on a first downlink shared channel amongthe plurality of downlink shared channels has been encoded using a firstMCS, modulation and coding scheme, different from a second MCS used fortransmitting the data on a second downlink shared channel from among theplurality of downlink shared channels.

In some exemplary embodiments, the circuitry, in operation, performssoft-combining on the data received on the plurality of downlink sharedchannels, decodes the combined data obtained by the soft-combining, andgenerates the indicator based on the result of the decoding of thecombined data.

Further embodiments provide a network node, comprising a transceiverwhich, in operation, transmits data on a downlink shared channel fromamong a plurality of downlink shared channels, the data transmitted onthe plurality of downlink shared channels being respectively the samedata, and receives, on an uplink control channel associated with thedownlink shared channel, an indicator which indicates whether or not thetransmitted data has successfully been received and decoded using theplurality of downlink shared channels, and circuitry which, inoperation, determines, based on the indicator, whether or not the datahas been successfully received and decoded.

For instance, said downlink shared channel from among the plurality ofdownlink shared channels is a first downlink shared channel, thetransceiver comprises a first TRP, transmission and reception point,and, in operation, transmits the data on the first downlink sharedchannel using the first TRP, receives the indicator on the uplinkcontrol channel associated with the first downlink shared channel usingthe first TRP, and the network node further comprises a backhaulinterface and transmits, over the backhaul interface, schedulinginformation for scheduling transmission of the data a second downlinkshared channel from among the plurality of downlink shared channels by asecond TRP.

According to some embodiments, said downlink shared channel from amongthe plurality of downlink shared channels is a first downlink sharedchannel the circuitry, in operation, encodes the data for transmissionon the first downlink shared channel using a first MCS, modulation andcoding scheme, different from a second MCS used for transmitting thedata on a second downlink shared channel from among the plurality ofdownlink shared channels.

In some embodiments, the indicator is a common indicator which indicatesa common result of decoding using at least two downlink shared channelsamong the plurality of downlink shared channels, the common indicatorbeing a one-bit indicator.

For instance, the common indicator indicates a result of a logical “OR”operation performed on respective results of the decoding of theplurality of downlink shared channels.

For instance, the transceiver, in operation, receives the commonindicator and a respective indicator indicating whether or not the datahas been successfully decoded using a respective downlink shared channeltransmitted by said network node.

For instance, the transceiver, in operation, receives an ACK/NACKacknowledgement/negative acknowledgement, signal including the commonindicator and the respective indicator.

For instance, the circuitry, in operation, receives the respectiveindicator before the common indicator, the respective indicator and thecommon indicator being received in separate ACK/NACK signals.

For instance, and the indicator includes a plurality of bits each ofwhich indicates whether or not the data has been successfully decodedusing a respective one of the plurality of downlink shared channels.

In some embodiments, the indicator indicates a result of the decoding ofthe combined data obtained by soft-combining of the data from theplurality of downlink shared channels.

Further provided is a communication method for a user equipment,comprising the steps of receiving data on a plurality of downlink sharedchannels, the data received on the plurality of downlink shared channelsbeing respectively the same data, decoding the data, generating anindicator which indicates whether or not the data has been successfullydecoded using the plurality of downlink shared channels, andtransmitting the indicator on at least one of a plurality of uplinkcontrol channels associated respectively with the plurality of downlinkshared channels.

In some embodiments, the indicator is transmitted on each of theplurality of uplink control channels associated respectively with theplurality of downlink shared channels.

For instance, the plurality of downlink shared channels are receivedrespectively from a plurality of TRPs, transmission and receptionpoints, and the indicator is transmitted on the plurality of uplinkcontrol channels respectively to the plurality of TRPs.

According to some embodiments, the indicator is a common indicator whichindicates a common result of decoding using at least two downlink sharedchannels among the plurality of downlink shared channels, the commonindicator being a one-bit indicator.

For example, the plurality of downlink shared channels are respectivelydecoded, and the method includes performing a logical “OR” operation onrespective results of the decoding of the plurality of downlink sharedchannels, and the common indicator indicates the result of the logical“OR” operation.

For instance, the method includes generating, for each of the pluralityof downlink shared channels, a respective indicator indicating whetheror not the data has been successfully decoded using the respectivedownlink shared channel, and the common indicator and the respectiveindicator indicating the result of decoding the downlink shared channelassociated respectively with the uplink control channel are transmittedrespectively on each of the plurality of downlink shared channels.

For instance, on each of the plurality of uplink control channels, anACK/NACK, acknowledgement/negative acknowledgement signal including thecommon indicator and the respective indicator is respectivelytransmitted.

In some embodiments, the respective indicator on each of the pluralityof uplink control channels is transmitted before accomplishingperforming the logical “OR” operation.

For instance, the plurality of downlink shared channels are respectivelydecoded, and the indicator includes a plurality of bits each of whichindicates whether or not the data has been successfully decoded using arespective one of the plurality of downlink shared channels.

For example, the data received on a first downlink shared channel amongthe plurality of downlink shared channels has been encoded using a firstMCS, modulation and coding scheme, different from a second MCS used fortransmitting the data on a second downlink shared channel from among theplurality of downlink shared channels.

In some embodiments, the method includes performing soft-combining onthe data received on the plurality of downlink shared channels, decodingthe combined data obtained by the soft-combining, and generating theindicator based on the result of the decoding of the combined data.

The disclosure further provides a communication method for a networknode, comprising the steps of transmitting data on a downlink sharedchannel from among a plurality of downlink shared channels, the datatransmitted on the plurality of downlink shared channels beingrespectively the same data, receiving, on an uplink control channelassociated with the downlink shared channel, an indicator whichindicates whether or not the transmitted data has successfully beenreceived and decoded using the plurality of downlink shared channels,and determining, based on the indicator, whether or not the data hasbeen successfully received and decoded.

For instance, said downlink shared channel from among the plurality ofdownlink shared channels is a first downlink shared channel, the methodcomprises transmitting the data on the first downlink shared channelusing a first TRP, receiving the indicator on the uplink control channelassociated with the first downlink shared channel using the first TRP,and transmitting, over a backhaul interface, scheduling information forscheduling transmission of the data a second downlink shared channelfrom among the plurality of downlink shared channels by a second TRP.

According to some embodiments, said downlink shared channel from amongthe plurality of downlink shared channels is a first downlink sharedchannel the circuitry, and the method comprises encoding the data fortransmission on the first downlink shared channel using a first MCS,modulation and coding scheme, different from a second MCS used fortransmitting the data on a second downlink shared channel from among theplurality of downlink shared channels.

In some embodiments, the indicator is a common indicator which indicatesa common result of decoding using at least two downlink shared channelsamong the plurality of downlink shared channels, the common indicatorbeing a one-bit indicator.

For instance, the common indicator indicates a result of a logical “OR”operation performed on respective results of the decoding of theplurality of downlink shared channels.

In some embodiments, the common indicator and a respective indicatorindicating whether or not the data has been successfully decoded using arespective downlink shared channel transmitted by said network node arereceived.

For instance, an ACK/NACK acknowledgement/negative acknowledgement,signal including the common indicator and the respective indicator isreceived.

In some embodiments, the respective indicator is received beforereceiving the common indicator, the respective indicator and the commonindicator being received in separate ACK/NACK signals.

For instance, the indicator includes a plurality of bits each of whichindicates whether or not the data has been successfully decoded using arespective one of the plurality of downlink shared channels.

In some embodiments, the indicator indicates a result of the decoding ofthe combined data obtained by soft-combining of the data from theplurality of downlink shared channels.

Summarizing, the present disclosure relates to a user equipment, anetwork node and respective communication methods for a user equipmentand a network node. A according to some embodiments, a user equipmentcomprises a transceiver which, in operation, receives data on aplurality of downlink shared channels, the data received on theplurality of downlink shared channels being respectively the same data,and circuitry which, in operation, decodes the data, generates anindicator which indicates whether or not the data has been successfullydecoded using the plurality of downlink shared channels. Thetransceiver, in operation, transmits the indicator on at least one of aplurality of uplink control channels associated respectively with theplurality of downlink shared channels.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A user equipment, comprising: a transceiverwhich, in operation, receives data on a plurality of downlink sharedchannels, the data received on the plurality of downlink shared channelsbeing respectively the same data; and circuitry which, in operation,decodes the data on the plurality of downlink shared channels,generates, for each of the plurality of downlink shared channels, arespective indicator which indicates whether or not the data has beensuccessfully decoded using the respective downlink shared channel;wherein the circuitry, in operation, performs a logical “OR” operationon respective results of the decoding of at least two downlink sharedchannels among the plurality of downlink shared channels, and generatesa common indicator which indicates the result of the logical “OR”operation, the common indicator being a one-bit indicator, thetransceiver, in operation, transmits, on each of a plurality of uplinkcontrol channels associated respectively with the plurality of downlinkshared channels, the respective indicator indicating the result ofdecoding the downlink shared channel associated respectively with theuplink control channel before the circuitry accomplishes performing thelogical “OR” operation, and the transceiver, in operation, transmits thecommon indicator on each of the plurality of uplink control channels. 2.The user equipment according to claim 1, wherein the transceiver, inoperation, receives the plurality of downlink shared channelsrespectively from a plurality of TRPs, transmission and receptionpoints, and transmits the respective indicator and the common indicatoron the plurality of uplink control channels respectively to theplurality of TRPs.
 3. The user equipment according to claim 1, whereinthe transceiver, in operation, respectively transmits, on each of theplurality of uplink control channels, an ACK/NACK,acknowledgement/negative acknowledgement, signal including the commonindicator and the respective indicator.
 4. The user equipment accordingto claim 1, wherein the respective indicators are a plurality of bitseach of which indicates whether or not the data has been successfullydecoded using a respective one of the plurality of downlink sharedchannels.
 5. The user equipment according to claim 1, wherein thecircuitry, in operation, performs soft-combining on the data received onthe plurality of downlink shared channels, decodes the combined dataobtained by the soft-combining, and generates the respective indicatorbased on the result of the decoding of the combined data.
 6. A networknode, comprising: a transceiver which, in operation, transmits data on adownlink shared channel from among a plurality of downlink sharedchannels, the data transmitted on the plurality of downlink sharedchannels being respectively the same data, receives, on each of aplurality of uplink control channels respectively associated with theplurality of downlink shared channels, a respective indicator whichindicates whether or not the transmitted data has successfully beenreceived and decoded using the respective downlink shared channel, andafter receiving the respective indicator, receives, on each of theplurality of uplink channels, a common indicator which indicates aresult of a logical “OR” operation performed on respective decodingresults of at least two downlink shared channels among the plurality ofdownlink shared channels, the common indicator being a one-bitindicator; and circuitry which, in operation, determines, based on therespective indicator and the common indicator, whether or not the datahas been successfully received and decoded.
 7. The network nodeaccording to claim 6, wherein said downlink shared channel from amongthe plurality of downlink shared channels is a first downlink sharedchannel, the transceiver comprises a first TRP, transmission andreception point, and, in operation, transmits the data on the firstdownlink shared channel using the first TRP, receives the respectiveindicator and the common indicator on the uplink control channelassociated with the first downlink shared channel using the first TRP,and the network node further comprises a backhaul interface andtransmits, over the backhaul interface, scheduling information forscheduling transmission of the data on a second downlink shared channelfrom among the plurality of downlink shared channels by a second TRP. 8.The network node according to claim 6, wherein said downlink sharedchannel from among the plurality of downlink shared channels is a firstdownlink shared channel and the circuitry, in operation, encodes thedata for transmission on the first downlink shared channel using a firstMCS, modulation and coding scheme, different from a second MCS used fortransmitting the data on a second downlink shared channel from among theplurality of downlink shared channels.
 9. A communication method for auser equipment, comprising the steps of: receiving data on a pluralityof downlink shared channels, the data received on the plurality ofdownlink shared channels being respectively the same data; decoding thedata on the plurality of downlink shared channels; generating, for eachof the plurality of downlink shared channels, a respective indicatorwhich indicates whether or not the data has been successfully decodedusing the respective downlink shared channel; performing a logical “OR”operation on respective results of the decoding of at least two downlinkshared channels among the plurality of downlink shared channels, andgenerating a common indicator which indicates the result of the logical“OR” operation, the common indicator being a one-bit indicator;transmitting, on each of a plurality of uplink control channelsassociated respectively with the plurality of downlink shared channels,the respective indicator indicating the result of decoding the downlinkshared channel associated respectively with the uplink control channelbefore the performing of the logical “OR” operation is accomplished; andtransmitting the common indicator on each of the plurality of uplinkcontrol channels.
 10. A communication method for a network node,comprising the steps of: transmitting data on a downlink shared channelfrom among a plurality of downlink shared channels, the data transmittedon the plurality of downlink shared channels being respectively the samedata; receiving, on each of a plurality of uplink control channelsrespectively associated with the plurality of downlink shared channels,a respective indicator which indicates whether or not the transmitteddata has successfully been received and decoded using the respectivedownlink shared channel; after receiving the respective indicator,receiving, on each of the plurality of uplink channels, a commonindicator which indicates a result of a logical “OR” operation performedon respective decoding results of at least two downlink shared channelsamong the plurality of downlink shared channels, the common indicatorbeing a one-bit indicator; and determining, based on the respectiveindicator and the common indicator, whether or not the data has beensuccessfully received and decoded.